Device for detachable fastening of an auxiliary wheel to a wheel of a vehicle

ABSTRACT

In a device for detachable fastening of an auxiliary wheel (2) to a wheel (1) of a vehicle, at least one tensioning device (3) is provided with which the auxiliary wheel can be tensioned against the wheel (1) via a distance sleeve (10). The tensioning device (3) has an anchor part (13) which is connected by a wheel bowl of the rim (4) of the wheel (1), and which is provided with an aperture (18) which has a passage (20) with a narrowing (19). A head (21) of a connecting rod (14) can be inserted into the aperture (18) of the anchor part (13), which head is held in the anchor part (13). Disposed on the connecting rod end (14) opposite the head (21) is a tensioning element (15) which can be hung up and tensioned in a part of the rim (8) of the auxiliary wheel (2). With this device the auxiliary wheel (2) can be easily tensioned on the wheel (1), the tensile forces which arise being optimally transmitted.

FIELD OF THE INVENTION

This invention relates to a device for detachable fastening of anauxiliary wheel to a wheel of a vehicle, in particular an agriculturalvehicle.

BACKGROUND OF THE INVENTION

It is often necessary with agricultural vehicles to enlarge thesupporting surface of the wheel for tilling the fields in order to keepthe soil pressure at a minimum. This is achieved by mounting anauxiliary wheel on each of the wheels of the vehicle. The mounting andthe removal of these auxiliary wheels should be achieved quickly andwithout great effort, since driving on roads with the mounted additionaltires is often not allowed owing to the over-dimensional width.Therefore it should also be possible to mount and remove the auxiliarywheels in the field, for example.

Also in the case of other vehicles, for example construction machines,which have to be driven in open country, it can be advantageous if thesupporting surface of the wheels can be enlarged, for example to preventsinking in a soft subsoil. The same device can be used here as for theaforementioned agricultural vehicle.

Devices of this kind are known. In these devices ring bolts areinstalled on the wheel of the vehicle, preferably on the wheel bowl,distributed about the circumference. Engaging in the ring of each ofthese bolts is a hook, which is formed at one end of the connecting rod.The other end of the connecting rod engages in a hook which can betensioned, which can be hung on the rim of the auxiliary wheel, andwhich can be firmly tensioned via a tension lever. The auxiliary wheelis hereby tensioned against a distance sleeve, mounted between the twowheels, and is tensioned with this sleeve on the wheel of the vehicle.The adjustment of the length of the tensioning means takes place byturning the connecting rod, which is screwed into the tensioning elementvia a threading. A device of this kind is described, for example, inEP-A-0 084 979.

A similar installation is described in U.S. Pat. No. 3,836,202. Here,too, a connecting rod is used whose one end is shaped as a hook and canbe hung in a ring-shaped screw fastened to the wheel. The other end ofthe connecting rod is provided with a threading on which a tensioningnut is screwed, which is supported on a claw which can be hung in theauxiliary wheel. To tension the tensioning means, the tensioning nutmust be tightened by means of screw spanner.

The driving forces of the wheel must also be transmitted to theauxiliary wheel through this prior art device tensioning means, disposeddistributed about the circumference. Consequently the force to beabsorbed by the tensioning means is relatively great. This means thatthe hook, which can be hung in the ring bolt, must be dimensioned big,or the number of tensioning means provided for attaching the auxiliarywheel must be increased. Nevertheless there is the risk that the hook ofan individual tensioning means might bend or even break.

The object of the present invention therefore consists in improving thetransmission of forces from connecting rod to anchor part such that thecorresponding elements can be dimensioned small so that material can besaved, or in the case of the same dimensioning, the number of tensioningmeans per wheel can be reduced so that costs can be lowered and themounting and removal of the auxiliary wheel can be achieved with lesseffort.

SUMMARY OF THE INVENTION

The inner annular surface of the anchor part, on which the head of theconnecting rod is supported, is preferably designed with a concave,spherical shape, the head being provided with a corresponding sphericalform. The transmission of forces can thereby take place optimally whenthe connecting rod is situated in an inclined position with respect tothe anchor part, for which purpose the passage of the anchor part has anoutwardly opening conical shape. Inclined positions of this kind canresult in particular with driven wheels in that the auxiliary wheelturns relative to the wheel of the vehicle, and through the inclinedposition of the connecting rods of the tensioning means, the pressingpressure of the auxiliary wheel is increased.

In that the anchor part is provided with a recess running transverselyfrom outside to the passage, so that the head of the connecting rod canbe driven laterally out of, or respectively into, the anchor part, asimple mounting and removal of the auxiliary wheel is possible.Moreover, the anchor parts can remain fastened to the wheel, forexample, even when the auxiliary wheel is not mounted.

A preferred embodiment of the invention consists in the anchor parthaving on the back side a bore, provided with a threading, by means ofwhich bore the anchor part can be firmly screwed to the wheel of thevehicle.

In order to achieve greater strength of the transition anchor part-headof the connecting rod, the narrowing with the annular surface, on whichthe head is supported, is set back toward the remaining walling of theanchor part in the direction opposite to the recess running transverselyto the passage. Stronger side walls result thereby in the area of therecess.

Further preferred embodiments of the invention result from the furtherdependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the device according to the invention will be explainedmore closely in the following, by way of example, with reference to theenclosed drawing. Shown are:

FIG. 1, which is a section through a wheel of a vehicle with anauxiliary wheel mounted thereon through tensioning means;

FIG. 2, which is a side view of a tensioning means with the anchoringpart, partially in section;

FIG. 3, which is a top view of a tensioning means with the anchoringpart shown in section;

FIG. 4, which is an end view of the anchoring part with the connectingrod removed; and

FIG. 5, which is a plan view of the anchoring part shown in FIG. 2, withthe tension released.

Shown in FIG. 1 is a wheel 1 with an auxiliary wheel 2 fastened thereonvia tensioning means 3. The wheel 1 consists of a rim 4 on which a tirehas been mounted. A wheel bowl 6 is fixed inside the rim 4, by means ofwhich wheel bowl the wheel 1 is fixed, for example, to the drive shaft 7of a vehicle (not shown) by means of screws.

The auxiliary wheel 2 likewise consists of a rim 8, on which a tire 9has been mounted. Fastened to the rim 8 of the auxiliary wheel 2 is adistance sleeve 10 in the form of an annular spacer. This distancesleeve 10 supports itself on a shoulder 11 of the rim 4 of the wheel 1,when the auxiliary wheel 2 has been mounted on the wheel 1.

Mounted on the inner side of the distance sleeve 10 is a surrounding webplate 12, which is firmly connected to the distance sleeve 10.

Fastened to the wheel bowl 6, distributed about the circumference, areanchor parts 13 of the tensioning means 3, preferably in the vicinity ofthe rim 4. With each anchor part 13 an end region of a connecting rod 14can be held, whose other end is provided with a tensioning element 15.Each tensioning element 15 can be hung in the surrounding web plate 12of the distance sleeve 10 and can be tensioned, by means of which theauxiliary wheel 2 with the distance sleeve 10 is tensioned against thewheel 1. Several tensioning means 3 can be disposed over thecircumference of a wheel 1, depending upon the size of the wheels 1 and2 to be connected, upon the dimensioning of the tensioning means 3 andupon the size of the forces to be transmitted. Two tensioning means 3suffice for minimal requirements; to meet greater demands it could befour or more tensioning means 3.

It is also conceivable that in the case of small wheels 1 and 2, inparticular if they are not driven, only one tensioning means 3 is used,which is installed in the center of the wheels 1 and 2. The auxiliarywheel 2 could likewise be provided with a wheel bowl, in the center ofwhich a hanging element for the tensioning element 15 would be disposed.

Visible in FIG. 2 is the rim 4 of the wheel 1 to which the wheel bowl 6is fixed. By means of screw 16, the anchor part 13 is fixed to the wheelbowl 6 in that this screw engages in a threaded bore 17 of the anchorpart 13. The anchor part 13 has an aperture 18, which is provided withan axial passage 20 having a narrowing 19. A head 21 of the connectingrod 14 is held by the narrowing 19.

The anchor part 13 has a radial recess 22 running transversely fromoutside to the passage 20, through which recess the head 21 of theconnecting rod 14 can be driven laterally out of, or respectively intothe aperature 18 of, the anchor part 13 in the unloaded state.

As is especially visible in FIG. 3, the narrowing 19 of the anchor part13 is provided with an inner annular surface 23, designed with aconcave, spherical shape. The head 21 of the connecting rod 14 has acorresponding, convex, spherical shape 24, which cooperates with theannular surface 23. The passage 20 of the anchor part 13 is providedwith an outwardly flared conical shape 25. By means of the sphericaldesign of the inner annular surface 23 and of the head 21, and by meansof the conical shape 25 of the passage 20, the connecting rod 14 can beinclined with respect to the anchor part 13 by a certain amount in anydirection, the transmission of forces from the connecting rod 14 to theanchor part 13 always being optimal also in the inclined position.

As can be seen from FIGS. 2 and 3, the area of the connecting rod 14remote from the head 21 is provided with a threading. The connecting rod14 can thereby be screwed into a threaded bushing 26, which is heldpivotable about an axis 27, in a tension lever 28 of the tensioningelement 15. The tension lever 28, for its part, is pivotably connectedto the tensioning hook 30 by means of hinge pin 29. At the distal end,the tensioning hook 30 has a catch hook 31.

By screwing the connecting rod 14 into the threaded bushing 26 of thetensioning element 15, the distance between the anchor part 13 and thetensioning element 15 can be set precisely, so that the tension forcebecomes optimal. This exact setting is made possible by the head 21,which is held optimally in the anchor part 13 in every turning position.

Shown in FIG. 2 is the tensioning element 15 in a tensioned state, whichmeans that the tensioning hook 30 is hung up in the surrounding webplate 12 of the distance sleeve 10, and the rim 8 of the auxiliary wheel2 is tensioned against the wheel 1 via the distance sleeve 10, thedistance sleeve 10 supporting itself on the shoulder 11 of the rim 4 ofthe wheel 1. The tensioning hook 30 has a support foot 32 in its regionremote from the catch hook 31, which support foot ensures that this areaof the tensioning hook 30 is spaced apart from the distance sleeve 10.

To release the tensioning element 15, an auxiliary rod is pushed intothe bracket 33 of the tension lever 28, whereby the tension lever 28 ispivoted away about the axis 27 of the threaded bushing 26 a incounterclockwise direction. This pivotal movement displaces the hingepin 29 to move in an arc about the pivot axis, whereby the tensioninghook 30 is moved toward the auxiliary wheel 2, and the catch hook 31moves out of the web plate 12. Tensioning takes place in reversesequence.

As can be seen from FIGS. 2, 3 and 4, the narrowing 19 extends betweenthe aperture 18 and the passage 20. The recess 22 is key-shaped andextends from outside to the aperture 18 and to both the aperature 18 andthe passage 20. The narrowing 19 is set back from the passage 20 towardthe remaining wall 34 of the anchor part 13. Stronger side walls resulttherefrom in the area of the recess 22 and the aperature 18, the tensilestrength of the anchor part 13 being improved where of the head 21engages the annular surface 23 of the narrowing 19.

The anchor part 13 can essentially have any desired circumferentialshape. This circumferential shape is preferably hexagonal so that theanchor part 13 can be held with a hexagonal key for screwing onto thewheel bowl 6.

With this device the tension forces, which result when putting anauxiliary wheel 2 on the wheel 1, are optimally absorbed andtransmitted. The mounting and removal of the auxiliary wheel 2 on, orrespectively from, the wheel 1 can be carried out very easily.

What is claimed is:
 1. A device for detachably fastening an auxiliarywheel to a main wheel of a vehicle, said wheels each having acircumference and a rim extending around said circumference, said devicecomprising an annular spacer supported at opposite ends on said rims,and a plurality of tensioning means disposed about said circumferencesto tension the auxiliary wheel against the main wheel via said annularspacer, at least one of said rims having a wheel bowl, each of saidplurality of tensioning means comprisingan anchor part connected to saidwheel bowl of said one rim, a connecting rod having a head engaging saidanchor part at one of its ends and having a hook member at the oppositeof its ends, said hook member adapted to engage the other of said rims,and releasable tension means to tension said connecting rod and tensionsaid hook member when engaged with the other of said rims, said anchorpart having an outside, an internal aperture receiving said head, aninternal passage receiving said connecting rod, an internal narrowingbetween said aperture and said passage, and a recess extending from saidoutside to said aperture, said narrowing and said passage, whereby saidconnecting rod may be detached from said anchor part through said recesswhen said tension means is released.
 2. A device according to claim 1wherein said narrowing has an inner annular concave spherical shapedsurface, and said head has a complementary convex spherical shapedsurface adapted to bear against said narrowing surface, said passagehaving a conical shape flaring outwardly from said narrowing.
 3. Adevice according to claim 1, wherein said anchor part has wall oppositesaid passage, and a threaded bore in said wall for connecting saidanchor part to said bowl.
 4. A device according to claim 1, wherein saidanchor part has a wall opposite said passage, said internal narrowingbeing set back from said passage toward said wall, said narrowing beingspaced from said wall a distance to permit said head to pass throughsaid recess when said tension is released.
 5. A device according toclaim 1, wherein said plurality of tensioning means include a common webplate fixed to and surrounding said other of said rims, said hook memberof each tensioning means engaging said web plate when said tension meansis operative.
 6. A device according to claim 1, wherein said connectingrod of said tensioning means includes a threaded end portion remote fromsaid head, and said hook member includes a threaded bushing toadjustably engage said connecting rod to said hook member.
 7. A deviceaccording to claim 1, wherein each of said releasable tensioning meansincludes a tension lever connected to the end portion of said connectingrod remote from said head, said tension lever being connected to saidhook member and operable to releasably tension said hook member whenengaged with the other of said rims.